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11 Jul 2010 11:13:15 IST

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IF U HAVE THE STRENGTH TO FACE REALITY THEN ANSWER THIS QUESTION: RATES 4 SURE

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HOW MANY ELECTRIC FIELD LINES ORIGINATE FROM A UNIT POINT CHARGE KEPT IN SPACE hint :the answer may not be an integer explain why and how the answers are coming about

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silent killer

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11 Jul 2010 11:29:18 IST

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in my view the electric field line itself is an hypothetical model to visualise it...

there are just waves around it in which if any charges are kept experiances a force...

so hw can we say how many lines are there?

but if the book says how many lines are there assuming it exists.it is infinity.

because ,the field lines arise from it is all directions (if it is a positive charge) ...

lata

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11 Jul 2010 11:41:05 IST

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sorry Mr. S.K the answer is not infinity .If that wud have been the case then q1(> q2) charge wud have the same flux thro' a gaussian surface which is not correct

lata

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11 Jul 2010 11:42:41 IST

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of course field lines are hypothetical but still have a finite value

hmmmmm main aisa kyun hoon

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11 Jul 2010 11:46:22 IST

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they have no fonite value it depends on ur coice suppose if u consider 5 from a unit charge then u should draw 10 from 2 units charge

lata

Hot goIITian

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11 Jul 2010 11:50:24 IST

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try out some geometry I mean concept of solid angles to solve this question

AIR 538 Asish

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11 Jul 2010 12:09:58 IST

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before it was considered to be 4pi lines of force from a single point .. but obviously this is wrong as infinite lines originate from a single point and there is a unique electric field associated with every direction. so the idea of 4pi lines of force originating from a point has been discarded.

lata

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11 Jul 2010 12:18:55 IST

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then tell me one thing Mr. ashish then why does flux depend on the magnitude of the charge

lata

Hot goIITian

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11 Jul 2010 12:20:23 IST

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flux is the no. of lines passing thro' a surface of unit area

silent killer

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11 Jul 2010 12:24:53 IST

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ASISH..HOW DO U SAY THE NUMBER OF LINES IS 4PIE WHICH IS INDEPENDENT OF Q ....

10904him

Hot goIITian

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11 Jul 2010 12:25:43 IST

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The answer is not infinity but depends on the charge density bcoz of Gauss Law

Total Flux=q/(epsilon0)

Flux*Area=No of field lines Ans

Though being a hypothetical concept the question is not correct its a n anomaly!

grand canyon

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11 Jul 2010 12:26:38 IST

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FLUX IS DEFINED AS THE NUMBER OF FIELD LINES EMINATING FROM A SURFACE. SO THE NUMBER OF FIELD LINES FROM THIS POSITIVE CHARGE IS Q/ E0.

FLUX IS DEFINED AS THE NUMBER OF FIELD LINES EMINATING FROM THE SURFACE THAT IS NUMBER OF LINES LEAVING - NUMBER OF FIELD LINES ENTERING THE SURFACE.

THE NUMBER OF FIELD LINES INDEED DEPEND ON THE MAGNITUDE OF THE CHARGE.

silent killer

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11 Jul 2010 12:28:38 IST

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FLUX*AREA=LINES

SO THE LINES ARE NOT CONSTANT AND IT DEPENDS ON THE AREA ..HOW IT IS POSSIBLE ??

lata

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11 Jul 2010 12:29:18 IST

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Mr. S.K. the question is asking for no. of field lines from a unit + charge

AIR 538 Asish

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11 Jul 2010 12:29:22 IST

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flux can be qualitatively defined as such .. .but the concept of no. of electric field lines HAS NO MEANING now .. Infinite lines of force originate from ANY CHARGE.. If you have HCV, then there is also a short ans. ques.. regarding its validity. .FLux is defined as E.dS and most old books will give defn as no. of lines/area .. but ANY new book (foreign author) will tell u that this is now not valid

grand canyon

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11 Jul 2010 12:30:46 IST

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The definition of FLUX is number of field lines EMINATING FROM THE SURFACE. ELECTRIC FIELD LINES ARE HYPOTETICAL SO DOES THE CONCEPT OF FLUX.Actually the question has no meaning and just playing with terms nothing else.

AIR 538 Asish

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11 Jul 2010 12:32:59 IST

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definition of flux is always E.dA ....... the old definition regarding no. of lines per unit area has been discarded......

Shahbaz

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11 Jul 2010 12:34:06 IST

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HOW CAN IT HAVE A FINITE VALUE

grand canyon

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11 Jul 2010 12:35:08 IST

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But this question is based on the old definition if some guy sets up a question like this one must put up this answer only. it is a question just for the sake of asking and for it u need to use to old definition what else can u do? IN REALITY BOTH ARE INFINITE. THERE IS NO SUCH THING AS ELECTRIC FIELD LINES. There is a mistake in my solution THERE WILL BE TOO SMALL FIELD LINES WHICH ARE EVEN SMALLER THEN MY GAUSSIAN SURFACE. THE QUESTION IS NO GOOD. YES NEW DEFINITION IS INTEGRAL E.dA

AIR 538 Asish

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11 Jul 2010 12:36:45 IST

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Dont worry .. this question will NEVER be asked in any SENSIBLE entrance exam .. If it does get asked in JEE .. it will be a para ..where ull have info .. ............ otherwise this question has no significance in todays era of physics (E/M)

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